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* [gcc r11-8765] stor-layout: Avoid DECL_BIT_FIELD_REPRESENTATIVE with NULL TREE_TYPE [PR101172]
@ 2021-07-18 23:28 Jakub Jelinek
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From: Jakub Jelinek @ 2021-07-18 23:28 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:2b99794806d83e47249fd7c05bf521caee1fdcd4
commit r11-8765-g2b99794806d83e47249fd7c05bf521caee1fdcd4
Author: Jakub Jelinek <jakub@redhat.com>
Date: Thu Jun 24 12:22:14 2021 +0200
stor-layout: Avoid DECL_BIT_FIELD_REPRESENTATIVE with NULL TREE_TYPE [PR101172]
finish_bitfield_representative has an early out if the field after a
bitfield has error_mark_node type, but that early out leads to TREE_TYPE
of the DECL_BIT_FIELD_REPRESENTATIVE being NULL, which breaks assumptions
on code that uses the DECL_BIT_FIELD_REPRESENTATIVE during error-recovery.
The following patch instead sets TREE_TYPE of the representative to
error_mark_node, something the users can deal with better. At this point
the representative can be set as DECL_BIT_FIELD_REPRESENTATIVE for multiple
bitfields, so making sure that we clear the DECL_BIT_FIELD_REPRESENTATIVE
instead would be harder (but doable, e.g. with the error_mark_node TREE_TYPE
set by this patch set some flag in the caller and if the flag is there, walk
all the fields once again and clear all DECL_BIT_FIELD_REPRESENTATIVE that
have error_mark_node TREE_TYPE).
2021-06-24 Jakub Jelinek <jakub@redhat.com>
PR middle-end/101172
* stor-layout.c (finish_bitfield_representative): If nextf has
error_mark_node type, set repr type to error_mark_node too.
* gcc.dg/pr101172.c: New test.
(cherry picked from commit 65371066d8967560e3508af4a804e0ddb90acee7)
Diff:
---
gcc/stor-layout.c | 5 ++++-
gcc/testsuite/gcc.dg/pr101172.c | 20 ++++++++++++++++++++
2 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 9f850c3951e..242452f2acf 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -2086,7 +2086,10 @@ finish_bitfield_representative (tree repr, tree field)
/* If there was an error, the field may be not laid out
correctly. Don't bother to do anything. */
if (TREE_TYPE (nextf) == error_mark_node)
- return;
+ {
+ TREE_TYPE (repr) = error_mark_node;
+ return;
+ }
maxsize = size_diffop (DECL_FIELD_OFFSET (nextf),
DECL_FIELD_OFFSET (repr));
if (tree_fits_uhwi_p (maxsize))
diff --git a/gcc/testsuite/gcc.dg/pr101172.c b/gcc/testsuite/gcc.dg/pr101172.c
new file mode 100644
index 00000000000..b9d098bb644
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101172.c
@@ -0,0 +1,20 @@
+/* PR middle-end/101172 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+union U
+{
+ int a[3];
+ struct
+ {
+ int a : 3;
+ struct this_struct var; /* { dg-error "field 'var' has incomplete type" } */
+ } b;
+};
+
+const union U hello = {.a = {1, 2, 3}};
+
+void foo()
+{
+ int x = hello.b.a;
+}
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